Rapid Thermal Processing (RTP) is a semiconductor manufacturing process for heating silicon wafers at high temperatures, often 1200 degrees Celsius or greater, in a relatively short period of time, for example, in several seconds or less. During cooling in an RTP tool, wafer temperatures must be brought down evenly so as not to subject the wafer to thermal shock. This heating is often achieved using high intensity lamps, or lasers. Controlling the wafer temperature is a key challenge in rapid thermal processing. Often, this is achieved by monitoring the temperature of the wafer and using pyrometry to control, in real-time, the power and intensity of the lamps. An array of pyrometers may be used to measure the temperature of a wafer and based on that temperature, output voltage of a driver for the lamps is determined. Thus, an RTP tool for rapid thermal processing of wafers often comprises an array of lamps for heating a wafer, a chamber containing the wafer, a support for the wafer, and an array of pyrometers for measuring wafer temperature coupled to the wafer or the support for the wafer.
Therefore, the inventors have provided an improved lamp driver and substrate processing tools incorporating same.